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321.
Due to economic decline and the recent rise in home foreclosure, many U.S. cities are faced with managing large acreages of vacant land. Interest in local food production on this land has the potential to dramatically reshape the composition of greenspace found within urban landscapes. This study examined how the conversion of vacant land to urban gardens and farms influenced arthropod generalist predator populations and their ability to support biocontrol services. We found that the abundance of Coccinellidae and Syrphidae, and the activity density of Carabidae, Formicidae, and Lycosidae were equivalent among vacant lot and urban garden sites. Dolichopodidae abundance and the activity density of Linyphiidae and Opiliones were reduced in urban gardens whereas Anthocoridae abundance and the activity density of Staphylinidae were greater within urban gardens relative to vacant lots. The biocontrol service supplied by generalist predators was measured using sentinel eggs (Helicoverpa zea (Noctuiidae)) and pupae (Sarcophaga bullata (Sarcophagidae) and Musca domestica (Muscidae)). We found no difference in the biocontrol of H. zea eggs or M. domestica pupae among the focal greenspaces. We found no difference in the removal of S. bullata pupae by predators in June 2010, whereas in August 2010 a greater proportion of pupae were removed in urban garden sites relative to vacant lots. Based on these findings, we discuss the potential of the urban landscape to support generalist predators and sustainable urban gardening and farming.  相似文献   
322.
This study examined the associations of substance use, psychological distress, and mental health services receipt with the structure and content of adolescent school‐based networks. Using data from the National Longitudinal Study of Adolescent Health, we found that substance use was associated with receiving more, but making fewer, peer nominations. It also was associated with less favorable network characteristics, such as low GPA. Services receipt was associated with receiving and making fewer nominations, less favorable network characteristics, and a lower likelihood of reciprocated best friendships. Psychological distress had fewer significant associations. All associations were modest in magnitude. Our results suggest the importance of considering multiple indicators of socioemotional problems and multiple dimensions of social networks in research on adolescent peer relations.  相似文献   
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324.
Color-blind racism has transformed how race scholars understand race relations in contemporary society. Previous researchers mainly utilized this theory to identify frames of color-blind racism in various social settings and interactions. What has received less attention, however, is how frames of color-blind racism are produced within material conditions in which social interactions and relations occur. In this study we use film reviews to exemplify how color-blind racism is produced in a specific materialist context—film reviews. Film reviews garner discussion among scholars for their impact on the box office revenues of films. Less attention is given to the content of these reviews and, particularly, how their writers address issues of race. This study provides a qualitative content analysis of film reviewer’s discussions of race in their reviews of twenty-first-century films featuring black protagonists to illuminate some ways in which mainstream and niche media outlets discuss race. Results suggest that the source of the reviews influences how race is considered and communicated among film reviewers. Mainstream reviewers differ widely from niche reviewers in both content and delivery in their discussions of race.  相似文献   
325.
The goal of this study was to examine how aspects of self‐regulation and negative emotionality predicted children's co‐operative and prosocial behavior concurrently and longitudinally using the National Institute of Child Health and Human Development (NICHD) Study of Early Child Care and Youth Development. Mothers completed measures of children's temperamental proneness to negative emotionality and self‐regulation at 54 months. Teachers and parents completed measures of children's co‐operative and prosocial behavior at 54 months, first grade, and third grade. A latent profile analysis of the temperamental variables revealed four profiles of children: those high in regulation and low in negative emotionality, those moderate in regulation and moderate in negative emotionality, those low in regulation and high in negative emotionality, and finally those who were very low in regulation but high in anger emotionality. Generally, children with profiles that were high or moderate in terms of regulation and low or moderate in terms of negative emotionality were rated as the most prosocial and co‐operative. Children with profiles that were less well regulated and who were high in negative emotionality (particularly anger proneness) were rated as less co‐operative and prosocial by parents and teachers.  相似文献   
326.
The Cochran–Mantel–Haenszel tests are a suite of tests that are usually defined as conditional tests, tests that assume all marginal totals are known before sighting the data. Here unconditional analogues of these tests are defined for the more usual situation when the marginal totals are not known before sighting the data.  相似文献   
327.
Robust tests for comparing scale parameters, based on deviances—absolute deviations from the median—are examined. Higgins (2004) proposed a permutation test for comparing two treatments based on the ratio of deviances, but the performance of this procedure has not been investigated. A simulation study examines the performance of Higgins’ test relative to other tests of scale utilizing deviances that have been shown in the literature to have good properties. An extension of Higgins’ procedure to three or more treatments is proposed, and a second simulation study compares its performance to other omnibus tests for comparing scale. While no procedure emerged as a preferred choice in every scenario, Higgins’ tests are found to perform well overall with respect to Type I error rate and power.  相似文献   
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329.
Sexual health education for young people is crucial not only for development of norms but also for protection against vulnerabilities during this stage in life. Although several systematic reviews have examined the effectiveness of peer-led sex education, none have focused on the extent of peer participation. The purpose of this review was to evaluate peer-led sexual health education interventions in more developed countries (MDCs). Electronic and manual searches across five social science, education, and medical databases were conducted. Fifteen articles were selected in total. Most (10 of 15) studies gave low or no responsibility to peers. The majority of articles found improvements in sexual health knowledge (13 of 14) and attitudes (11 of 15) at postintervention stages. Two studies showed improved self-efficacy, and three showed behavioral changes. A preliminary synthesis of effectiveness and level of participation was done. Meta-analysis revealed a large effect on knowledge change (Hedges’ g = 0.84, 95% confidence interval [CI]: 0.43 to 1.25) and a medium effect on attitude change (Hedges’ g = 0.49, 95% CI: 0.19 to 0.80). Peer-led interventions could be a powerful tool. This review shows that this approach is effective in changing knowledge and attitudes but not behaviors. Further research and action are needed to understand optimal implementation.  相似文献   
330.
Through a representative sample of 9,100 and 8,755 employees in 2008 and 2010, and a using two-stage structural equation model, this article empirically analyses the multi-dimensional determinants (direct effects) of job quality in Spain. The research concludes that: #1 despite the economic crisis, job quality improved over the analysis period; #2 there was a shift in job quality explanation towards a more complete model with greater preponderance of the dimensions connected with the workplace relationships, work intensity, working conditions and work–life balance in detriment to dimensions connected with the intrinsic job quality and extrinsic rewards. These results suggest the importance of the working environment and social relationships, beyond the quality of the workplace, as important tools of employment public policy to improve labor markets and to overcoming the economic crisis.  相似文献   
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